Rear mounted log loader



Jan. 9, 1968 J. M.l EWART REAR MOUNTED LOG LOADER 6 Sheets-Sheet 1 FiledJune :3, 1966 FIG.

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Jan. 9, 1968 J. M EWART 3,362,549

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' REAR MOUNTED LOG LOADER Filed June 2, 1966 6 SheetfSheet 6 UnitedStates Patent REAR MOUNTED LOG LADER .lames Mervin Ewart, 525 AldoraunAve., Nanaimo, British Columbia, Canada Filed June 2, 1966, Ser. No.554,725 Claims priority, application Canada, Mar. 8, 1966, 954,130 12Claims. (Cl. 214-147) ABSTRACT F THE DISCLOSURE A log loadingarrangement in which a boom and tong assembly is combined with a yardingspar tree o-n a mobile platform or carrier. The boom and tong a-ssembly,while being mounted -rotatably on the mobile carrier, is operativelysuspended from the top of the spar tree.

This invention relates to logging and in particular to a combinedyarding and log loading apparatus.

In accordance with presently known practice, devices for loading logsthat have :been yarded consist of lifting cranes of the power shoveltype that have been suitably adapted for logging work. An example ofsuch a machine is shown in U.S. Patent No. 2,903,146 to Melay of Sept.8, 1959. In such machines a lifting boom is raised or lowered by thewell known gantry arrangement in which a line passes over a block orfairlead at the tip of the boom and is attached t-o a set of loggripping tongs. The operator actuates the mechanism so that the tongsgrip the log substantially centrally but towards the rear or heel of thelog. As lifting begins, the rear portion of the log is heeled againstthe bottom side of the b-oom to be held in this position while themachine rotates on its carrier to position the log over a truck and thetongs are then lowered and released.

A loading device according to the above description has numerousinherent disadvantages. For example, it requires 20,000 to 30,000 lbs.of counterweight to compensate for boom and load weight. -In addition tothis, the boom, machinery deck, winch and house etc., constitute asubstantial mass that c-an -be rotated only slowly.

The present invention overcomes the above disadvantages in providing aloader mounted in combination with a mobile spar tree such as thatIshown in U.S. Patent 3,015,471 of Jan. 2, 1962 and Canadian Patent No.657,909 of Feb. 19, 1963. In this combination, a boom and jibarrangement is rotatably mounted to the mobile spar tree vehicle and issuspended from the t-op of the spar. As such, the loader issubstantially lighter and less rigid than the boom of a conventionalloader; the need for counterweights is eliminated due to the method ofsuspension; a greater range or reach is provided; and, in view of thelow mass, speed of operation is substantially increased over knownloaders.

`In the previously mentioned United States and Canadian patent-s, it hasbeen described how a mobile spar tree provides many advantages overnatural spars or those mounted on railway tracks. An embodiment of sucha mobile spar is shown in FIGURE 1 of the accompanying drawings. Mobilespars have since shown their superiority in increased area clearing.

lt is, however, desirable to maintain the yard or log collecting areaaround the spa-r las clear as possible. This is not always the case dueto the fact that it has normally been necessary to include in the yardone or more log loading machines to clear away the area of accumulatingcuttings.

As will be seen from the drawings, the present invention provides Ilogloading means in combination with the 3,362,549 Patented Jan. 9, 1968ICC spar thereby obviating the need for additional loading vehicles.

In accordance then to one aspect of the present invention there isprovided, in combination with a spar tree mechanism, a rotatable logloader comprising a boom pivotally secured at one end Ito said spar treemechanism; a jib secured for pivotal movement to the other end of saidboom; a log gripping tong assembly pivotally mounted to the jib yat theend thereof remote from the boom; suspension lines interconnecting theupper end of said spar tree with the boom and tongs for support thereof;and means for rotating said boom, jib and tongs relative to the spartree mechanism.

The above and other aspects of the invention will more readily :beunderstood from reference to the accompanying drawings illustrating theinvention by way of example and in which;

FIGURE 1 is a schematic elevation view of the log loader mounted on andin combination with a mobile spar tree;

FIGURES 2 and 2a illustrate respectively two embodiments of suspendingthe boom and jib of the loader;

FIGURE 3 shows a further method of boom and jib suspension illustratingthe tongs and the means for actuating boom and jib movement;

FIGURE 4 is a schematic illustration of the mechanism for rotating theboom assembly; and

FIGURES 5, 6 and 7 illustrate several means for maintaining a log inlevel orientation during lifting and transport.

Referring to FIGURE 1, a tracked carrier illustrated generally at 10supports a collapsible spar tree 12 mounted on the car-rier 10 -bysuitable support 14 and secured in position by guylines 16 and 1S inaccordance with the patents mentioned. The carrier includes a yarder 20to actuate sheaves 22, 24 and their respective lines 26, 28 in order tocollect cut logs (not shown) to the immediate area.

In `accordance with FIGURES 1, 2, 2a, and 3, a log loading arrangementindicated generally at 30 is mounted on a turntable 32 rotatably securedto the rear of the carrier 10 that is given additional support at 34,the loading arrangement 30 consisting basically of a :boom 36, jib 33and tong assembly d0. Preferably, the boom 36 is of box-likeconstruction and the inner end thereof is pivotally mounted to theturntable 32, for example between flanges 42 by a pivot pin 44. The jib36 has a pivotal mounting at both of its ends. Its inner end 46 (thatnearest the carrier 10) is secured for swinging movement at 48 on, andrelative to, the outer end of the boom 36 while the outer or remote endS0 ofthe jib is similarly secured to the tong assembly 40. The latterincludes self closing tongs 52 and log levelling means in the form of aheeler 54.

As shown in FIGURE 2, the boom arrangement 30 is raised or loweredrelative to the turntable 32 by suspension lines. A lfirst line 56 isconnected at one end to the tong assembly 40 and terminates at its otherend in a pulley block 58. A second line 60 is utilized to raise theother end of the boom 35 and this line may be arranged in threeembodiments. In FIGURE 2, line 60 is secured at one end to the cute-rend of boom 36 adjacent its connection to jib 3S. The line then isplayed around a 'lirst upper pulley 62; downwardly and around pulley 58;then back up overa second yupper pulley 64 and thence to a boom hoistunit 66 located on the carrier 10 adjacent the turntable 32. It will benoted from FIGURE 2 that upper pulleys 62 and 64 are mounted in a commonblock 68 connected to a swivel mounting 70 atop the spar tree 12.

In the embodiment of FIGURE 2a, line 60 is secured at its free end 61 tothe pulley 5S and is then played about pulley 62, back downwardly aroundpull-ey 58 and thence around upper pulley 64 and down to hoist unit 66.

ln the FIGURE 3 embodiment, the rst line 56 is also connected at one endto the tong assembly 40 and is also provided on its free end with thepulley block S5. However, swivel mounting 70 retains only one upperpulley 62a and its associated block 68 has a free end of the line 60secured thereto. Line 60 then proceeds from block 68; around lowerpulley S; around upper pulley 62a to a boom pulley 72 and thence to thehoist unit 66 which, in this embodiment, is mounted within the confinesof the structure of boom 36. It will be noted that the unit 66 includesa driven suspension line drum 74 actuated for example by a pair ofhydraulic motors 76. From either embodiment it will be evident that adrawing-in or lettingout of line 60 by the hoist unit 66 will raise orlower, respectively, the whole boom arrangement 30.

Hydraulic means for swingint7 the boom system 30 in an arc from itscarrier position throughout a substantial area of the yard is indicatedgenerally at 78 in FlGURE 3 and is .shown in a schematic circuit inFIGURE 4 of the drawinns. A turntable such as 32 in the present devicemay be powered in various ways such as by a hydraulic motor but whentorque requirements are very high and the rate of swing is slow (both ofwhich apply to the environment of the present invention), high speedhydraulic motors coupled with .speed reducers become extremely costly. Arack and pinion arrangement powered by slow moving cylinders is afurther method of turntable rotation but substantial room must beprovided for the racks to extend at the end of piston travel. A cableand sheave arrangement constitutes a third method but an inherentdisadvantage is the stretching of the cable which then becomes loose onthe drum.

The turntable rotating device 78 of FIGURE 4 utilizes a chain andsprocket arrangement including means to prevent chain jumping.

Turntable 32 is axially connected to a sprocket 70 about which iscirculated a drive chain 72 having little appreciable stretch. Each endof chain 72 is respectively connected to the free ends of piston rods74a and 74h extending rom cylinders 76a and 76h that serve to enclosepistons 78a and '73b as shown. Each cylinder includes a rod end 30 and ablind end 82. The rod ends are interconnected by a fluid line 84incorporating a pump 36 and relief valve 88. The blind ends of cylinders76a and 76b are connected by lines 90 to a manual control valve 92provided with an adjacent pump 94. Lines 90 include relief valves 96, 98and restrictors 100.

With valve 92 in a neutral position, there is Zero pressure on the blindends 82 of the cylinders, full pressure, say in the region of 2000 to2500 psi., being maintained on the rod ends 00 by pump 36 and regulatedby relief Valve 88. in this neutral position the rotating system isbalanced and no revolving of the turntable 32 takes place, although fulltension is maintained on the chain 72. By

ianually actuating control valve 92 either one way or the other,pressure from pump 94 is introduced via lines 90 into the blind end 82of one of the cylinders, say for example 76b. This upsets the balancedcondition by transferring pressure on the rod end 80 of cylinder 7Gb tothe rod end of cylinder 76a to thereby rotate the sprocket 70, turntable32 and the associated boom arrangement 30. Relief valves 96 and 98protect the cylinders from over pressure and the restrictors 100 absorbHuid leakage past the pistons 73a and 73!) and returns the tluid to areservoir (not shown).

rhe effective reach of the loader 30 (notwithstanding boom and jiblength) is controlled both by raising and lowering the outer end of boom36 by suspension line 60 and through actuation of the hydraulic jibcylinder 102, shown in FIGURE 3, that is connected at one end to theboom 36 and at the other end to the jib 33 adjacent its upper end, i.e.that end close to the jib-boom connection.

It Will be appreciated that known methods of holding a log in a tongassembly and heeling it against the underside of the boom are quiteunsatisfactory, making levelling of the log very difficult duringloading operations. It also limits the extent to which the log may betilted. FIGURES 5, 6 and 7 of the drawings illustrate three methods oflog tilt control developed to increase the range of log tilt, obviatethe necessity of boom-heeling a log prior to lifting it; and whereby thelog may automatically be maintained in level or substantially levelorientation during picking-up and loading thereof.

As shown in FGURE 3, a hydraulic cylinder 104 iS mounted between the jib38 and to toothed heeler 54 of the tong assembly 40. Actuation of thiscylinder 104 governs the amount of ypivotal movement between the tongassembly 40 and jib 3S and thus the angle of tilt on the log L as well.

Referring now to FlGURE 5 there is shown an actuating control forcylinder 104 effected either automatically through a control valve 106and pendulum valve 108 or manually through valve 110, this choice beingdependent on the position of a switch valve 112. Pump 114 is associatedwith valves 106 and 110 while pump 116 and relief valve 118 areassociated with the pendulum valve 108.

It is evident from FIGURE 5 that when switch valve 112 is positioned forautomatic control, manual valve 110 is by-passed in the circuitry andcontrol passed to valve 106. Pendulum valve 108 detects hydraulicallythe amount of tilt on the log and it sends a pilot signal to actuatevalve 106 to retract or extend cylinder 104 according to the reach ofthe boom 36 being effected by cylinder 102 thereby to maintain the logsubstantially horizontal. it will be noted that the pendulum 10861 isdisposed in a tluid such as oil 109 to dampen its action and to reducehunting or erratic action.

A second embodiment for log levelling is shown in FIGURE 6. Here again,cylinder 104 is connected between the jib 38 and heeler 54 and may bemanually actuated by control valve through lines 117 and manual switchvalve 119. For automatic level control, iiuid is controlled by a camactuated valve 120, the cam 122 rotating in response to boom reach. Tongassembly i0 is provided with a sprocket 124 as is the inner end of theboom 36 with a sprocket 126, to which the cam 122 is mounted. At thejunction between the jib 38 and boom 36 two sprockets 128 and 130 areaxially connected. A rst chain 132 interconnects sprockets 124 and 128while chain 134 interconnects sprockets 126 and 130.

As the boom 36 is extended or retracted in reach by cylinder 102, thechain transmission `will rotate cam 122 to actuate valve to effectlevelling of the log through automatic manipulation of cylinder 104.

Turning now to FGURE 7, a still further method of log tilt controlcomprises three sheaves 133, 135 and 137 all of equal diameter mountedat the connections of boom-to-turntabie; boom-to-jib; and jib-to-tongs,respectively with sheave 137 being welded to the tong assembly A cable138 is secured at one end to tong 40 and is passed over the remainingsheaves 135 and 133 and is a parallelogram action which ensures aconstant angle of log tilt during movement of the boom 36 and jib 38.However, this angle may be' varied by means of a cylinder 140, placedintermediate the cable ends and actuated by a valve 142 via lines 144.Once the log angle is set, whether the log be horizontal or tilted, itwill not change regardless of boom and jib movement.

I claim:

1. In combination with a mobile carrier; a spar tree mounted on thecarrier; a rotatable log loader suspended from the top of said spar treeand mounted on said carrier, said loader including; rotation means 0nthe carrier; a boom pivotally secured at one end of said rotation means,a jib secured for pivotal movement to provided with a weight 139 at itsinner free end to create* the other end of said boom, a log grippingtong assembly mounted to said jib remote from said boom; swivel meansmounted for rotation atop the spar tree; suspension linesinterconnecting the upper end of said spar swivel means and the treewith said boom and tongs for pivotal and rotational support thereof; andmeans for rotating said boom, jib and tongs relative to said spar treeand its carrier.

2. In combination with a mobile carrier mounting a spar tree, arotatable log loader suspended .from the top of said spar tree andincluding, a turntable rotatably mounted on said carrier adjacent thebase of said spar tree; a boom pivotally secured at one end to saidturntable; a jib secured for pivotal movement to the other end of saidboom; means for extending said jib relative to the boom; a log grippingtong assembly pivotally mounted to said jib remote from said boom;swivel means mounted for rotation atop said spar tree; suspension linesinterconnecting the swivel means and the upper end of said spar treewith said boom ad tongs for pivotal and rotational support thereof; andmeans for rotating said boom; jib and tongs relative to said spar treeand carrier.

3. A log loader according to claim 1 including a hoist unit on saidcarrier adapted to actuate said suspension lines for vertical movementof said boom, jib and tong assembly relative to said carrier.

4. A log loader according to claim 2 wherein said jib extending meanscomprises a hydraulic cylinder connected at one end to said jib and atthe other end to said boom.

5. A log loader according to claim 1 wherein said boom, jib and tongrotating means comprises a turntable rotatably mounted on said carrieradjacent the base of said spar tree; a sprocket axially connected withsaid turntable; a pair of hydraulic balanced cylinders including pistonsand rods extending therefrom; transmission means interconnecting saidsprocket with the terminal ends of said piston rods; pump means formaintaining pressure on either end of said pistons; and a control valvefor transferring said pressure from one cylinder to the other to effectrotation of said sprocket and to maintain tension in said transmissionmeans.

6. In combination with a mobile carrier; spar tree mounted on thecarrier a rotatable log loader suspended from the top of the spar treeand including a boom pivotally secured at one end to said spar treecarrier; a jib secured for pivotal movement to the other end of saidboom; a hydraulic cylinder interconnecting said jib and boom forextending the reach of the jib; a log gripping tong assembly pivotallymounted to said jib remote from said boom; swivel means mounted forrotation atop the spar tree; suspension lines interconecting the swivelmeans and the upper end of said spar tree with said boom and tongs forpivotal and rotational support thereof and to eifect vertical movementof said boom relative to the carrier; means for rotating said boom, jiband tongs relative to said spar tree comprising a turntable rotatablymounted on said carrier; a sprocket axially connected to said turntable;a pair of pressure balanced hydraulic cylinders adapted, when actuated,to extend and retract with respect to one another; tensionedtransmission means interconnecting said cylinders to the sprocketwhereby extension and retraction of said cylinders effects rotation ofsaid sprocket, turntable and boom; and means for selectively andautomatically adjusting the orientation of the tong assembly withrespect to said jib for levelling a load carried by said tong assembly.

7. A log loader according to claim 6 wherein said hydraulic cylindersinclude pistons and rods projecting therefrom, the transmission meanscomprising a chain engaging the sprocket with each end of said chainbeing connected to an associated piston rod and a control valve formaintaining said chain under tension during rotation of the sprocket.

8. A log loader according to claim 6 wherein the tong adjusting meanscomprises a hydraulic cylinder interconnecting said jib and tongassembly; a manual control valve connected to said cylinder by uid linesfor selectively extending or retracting the tong assembly relative tothe jib; and a pendulum valve also connected to said cylinder by fluidlines to automatically adjust and extension or retraction in response toboom reach and the angle of the tong assembly set thereby.

9. A log loader according to claim 6 wherein the tong adjusting meanscomprises a hydraulic cylinder interconnecting the jib and tongassembly; a manual control valve connected to said cylinder by fluidlines for selectively extending or retracting the tong assembly relativeto the jib; a first sprocket connected to the tong assembly; a secondsprocket mounted on the inner end of said boom and a pair of furthersprockets axially connected together at the pivotal junction betweensaid boom and jib; transmission means interconnecting the first sprocketwith a sprocket of said further pair and also between the secondsprocket and the remaining sprocket of said further pair; an automaticcontrol valve interconnected to said cylinder through said uid lines;and a cam secured to said second sprocket on the boom adapted, when thereach of said boom is adjusted, to actuate said automatic control valveto effect extension or retraction of said cylinder in response to thereach of the boom.

10. A log loader according to claim 6 wherein the tong adjusting meanscomprises a irst sheave rigidly secured to the tong assembly; a secondsheave co-axially secured. intermediate the boom and jib, to the pivotalconnection therebetween; and a third sheave co-axially mounted with thepivotal connection of the boom to said turntable; a cable secured a oneend to the irst sheave and extending over said second and third sheaves;all of said sheaves being of identical diameter whereby adjustment ofthe reach of the boom effects a corresponding adjustment in the angle ofsaid tong assembly with respect to the jib; and means for selectivelyaltering the length of said cable.

11. A log loader according to claim 8 including a switch valve fortransferring actuation of said cylinder from manual to automaticcontrol.

12. A log loader according to claim 10 wherein the selective adjustingmeans comprises a hydraulic cylinder intermediate the ends of saidcable; a pump for supplying fluid to said cylinder through uid lines;and a valve for directing said fluid.

References Cited UNITED STATES PATENTS 3,120,310 2/ 1964 Roberts et al214--147 3,204,795 9/ 1965 Larson 214--147 GERALD M. FORLENZA, PrimaryExaminer.

HUGO O. SCHULZ, Examiner.

